Jonathan d



{No Model.)

J. D. MAWHOOD.

GRINDING MILL.

No. 453,981. Patented June 9,1891.

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ATT RN Y- UNITED STATES PATENT OFFICE,

JONATHAN D. MAYVHOOD, OF RICHMOND, INDIANA, ASSIGNOR TO THE RICHMONDCITY MILL WORKS, OF SAME PLACE.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent N 0. 453,981, dated June 9,1891.

Application filed August 22, 1889. Serial No. 321,68 2. (No model.)

in which- Figure l is a side elevation of such portions of adouble-roller mill as are necessary to an understanding of my presentimprovements, the tie-bar F being omitted at the right of the centralline in this figure, and the lugs 'l of that portion of the barappearing in vertical section; Fig. 2, a plan of the same showing onlyportions of one pair of rolls, the mountings at the rear side of themill being entirely omitted and the levers on the front side at theright appearing in horizontal section; Fig. 8, a side elevation of oneof the levers of one of the inner rolls, (shown detachefih) Fig. 4, aplan of one of the tie-bars F; Fig. 5, an end elevation of this bar; andFig. 6 a side elevation, the same as at the left of Fig. 1, butenlarged, of the end of one of the bars F, showing the adjusting-screw Hand its friction arrangement.

In the drawings, A indicates the body or frame of a double roller-mill;B, the inner rolls; C, the outer rolls; D, the levers or arms carryingat their upper ends journal-boxes for the outer rolls, the lower ends ofthese levers being pivoted to lugs projecting out from the sides of theframe; E, the pivots at the lower ends of these levers; F, a bardisposed horizontally alongside each side of the mill-frame and parallelwith the side thereof and outside the levers D, these tie-bars beingrigidly bolted to the sides of the frame, bosses or stretcher-blocksbeing interposed between the bars and the sides of the frame to give theproper distance between the bars and the frame; G, the bosses orstretcher-blocks just referred to, these bosses being preferably castupon either the frame or the tie-bars or a portion on each; H, theadjusting-screws provided with handles screwing inwardly through lugs atthe outer ends of the tie-bars, the inner ends of these screws bearingagainst the outer surfaces of the levers D, these screws thus serving asmeans for adjusting the outer rolls to and from the inner ones, thescrews being provided with lock-nuts to act in conjunction with the lugswhich the screws engage; J, spring-washers interposed between saidlock-nuts and lugs, these washers being radially slitted and so sprungthat they present a tooth, so to speak, to the face of the lock-nut, andanother tooth to the face of the lug, the direction of resistance ofthese teeth being such as to prevent the unscrewing of the lock-nut; K,a pair of shafts disposed across the mill-frame between and parallelwith the inner rolls, these shafts being journaled in the tie-bars andhaving at each end of each shaft an eccentric portion disposed justinwardly beyond the tie-bars; L, a hand-lever secured to the end of oneof these eccentric-shafts and serving as a means by which that shaft maybe rotated, such a lever being provided at each side of the millthat is,front and rear, if desiredso that the eccentric-shaft may be operatedfrom either side of the mill; M, a short crank secured to the other oneof the eccentric-shafts; N, a link connecting this crank with a similarcrank projecting from the lever L; 0, the crank just referred to asprojecting from the lever L, the two cranks being so disposed withreference to the eccentrics of the shafts that when both eccentricsoccupy their outermost positions the two cranks M and 0 will besubstantially at right angles to each other, as indicated in Fig. 1; P,levers supporting the inner rolls, these levers having the journal-boXesfor the inner rolls formed at their upper ends and being pivoted on theeccentrics of the shafts K at a point midway of the length of thelevers; Q, springs, one engaging between each pair of levers D P, thespring acting inwardly against the lower end of the lever P andoutwardly against the intermediate portion of the lever D; R, anadjusting-screw for each of these springs,

serving as a means by which the strength of the spring may be adjusted;S, set-screws, one for each journal-box of caclrinner roll, theseset-screws screwing into lugs in thetiebars and projecting upwardlytherefrom and presenting their upper ends under the journal-boxes of theinner rolls; T, lugs on the tie-bars F, adapted to receive the screws IIand S.

The tie-bars F, when bolted in position, form,in connection with theframe-slots outside the mill-frame, which slots contain the general rollmountings. These tie-bars take the tensional strains and introducefeatures of strength exterior to the roll-levers. They furthermorepermit of a peculiar economical and accurate system of manufacture.These bars being properly fitted up and their contiguous motion partsattached to them, the parts may be readily supported contiguous to theframe by means of a proper templet corresponding with the fourroll-shafts. The bolts which are to secure the tie-bars to the frame maythen be put in place, but not screwed up tightly. The bosses G are to beof such length that when the parts are thus temporarily mounted therewill be a space between the ends of the bosses and the parts whichattach to them. Soft metal, as Babbitt metal, is then poured in thesespaces, after which the bolts are permanently tightened. Aninterchangeable system of construction is thus provided independent ofirregularities in the casting of the heavy frame.

By inspecting Fig. 1 it will be noticed that the tendency of the springsG is to press the outer rolls outwardly. The screws H serve in adjustingthe grinding relation of the rolls, and the springs thus keep the leversD outwardly against the screws. The adjustment effect by the screws llis a delicate one, and the jarring of the mill in running might tend todisturb the adjustment. The use of locknuts on these screws as lock-nutsare ordinarily used would not be permissible, because the adjustmentrequires to be made often and easily and accurately. Ordinary lock-nutswould require to be loosened before the screws could be turned, and thetightening up of the lock-nuts would puta strain on the screws whichwould disturb the accurate adjustment. Furthermore, the unscrewing ofthe screws would slacken the lock-nuts and defeat their object. Iintroduce the toothed spring-washers between the lock-nuts and the lugs.These washers produce an outward pressure 011 the lock-nuts and thuscreate a friction on the thread of the screw, and this friction issufficient to prevent accidental displacement of the screws withoutinterfering with the screws being turned properly in either direction byhand. The frictional effect may be increased by tightening up thelock-nuts a trifle, thus causing the spring washers to act with greaterforce. It the locknuts be screwed up so tightly as to become lock-nutsin fact, then the device will become inoperative for the purposesdesired. The device thus differs in construction and mode of operationfrom that numerous class of locknuts in which a non-rotary screw has itsnut prevented from rotation by means of a tooth acted on by a spring. Itis essential to this particular feature of my invention that the screwbe a rotatable one and a lug through which it screws a non-rotatableelement. The inner rolls are held toward the outer rolls by the actionof the springs inwardly against the lower ends of the levers P. A hardsubstance accidentally reaching the rolls will cause the inner rolls toswing inwardly, the springs yielding to permit this, and upon thepassage of the substance-the springs will restore the rolls to theirnormal posit-ion. The same spring at one end of one pair of rollstherefore serves in furnishing the inner roll with the quality ofyielding upon the passage of a hard substance and furnishes the outerroll with an outward elastic pressure, against which the inwardadjustment for grinding distance may be made by means of the screw II.The roll B approaches and recedes from roll 0 in yielding to hardsubstances with a more or less vertical motion. The weight of roll Btends to urge it toward roll 0, and the tendency in action might be tojam the two rolls together. ize the weight of roll B to produce thegrinding pressure supplemented by springs Q, it is of importance toprevent the improper descent of roll B.

In order to prevent roll B from being jammed together with the roll G,the setscrews S are arranged under the bearings of roll B. Theseset-screws serve in determining the angle of approach as the roll B descends, thus regulating the grinding pressure due the weight of roll B,and they also serve in determining the relative descent of the two endsof the roll B, thus providing for insuring that the rolls B 0 shall atall times be parallel to each other. It will be found that by arrangingthe rolls perfectly parallel to one another a great saving in power willbe effected and the wear of the rolls lessened. The set-screws S andtheir performance in conjunction with roll B, carried in levers pivotedon eccentrics, are old and well known, (see English Patent No. 3,328 of1887,) and I therefore claim no novelty for these matters.

The levers P are pivoted on the eccentrics of the shafts K, but in theordinary working of the mill these shafts are stationary shafts, and theeccentrics then act merely as pivots on which the levers P may rock incase a f0reign body passes the rolls; but by operating the hand-lever Lin an obvious manner the eccentrics will rotate, and the pivots are thusmoved farther inwardly, thus opening the rolls. The cranks M and O andlink N serve in communicating rotary motion between the twoeccentric-shafts,and the relation of thetwo shafts to each'other is suchthat when the cccentric-shafts are in normal workin g position \Vhile itis desirable to utilthey will practically be locked. There is of courseto be a stop to, determine the normal working position of the hand-leverL. Such a stop is furnished in the exemplificati-on by the journal-boxof one of the inner rolls, against which the hand-lever rests. WVhen theinner rolls are moved inwardly by the action of the eccentric-shafts,the j ournalboxes of these rolls slide on the heads of the screws S, andthe springs are thus prevented from neutralizing the opening effect ofthe eccentrics.

The drawings illustrate the mountings upon one side of the mill only. Itwill be understood, of course, that the mountings at each end of therolls are the same. Some of the features referred to are of courseapplicable to mills having but a single pair of rolls.

I claim as my invention- 1. In a roller-mill, the combination,substantially as set forth, of a mill-frame, an inner and an outer roll,pivoted levers carrying the journal-boxes of said rolls and disposedexterior to the mill-frame, a tie-bar secured to and parallel with themill-frame and exterior to said levers, and an adj Listing-screw foradjusting the position of each journal-box lever of one of said rolls,said adj Listing-screw and the supporting-pivot of the journal-box leverof the other roll being supported by said tie-bar.

2. In a roller-mill, the combination, substantially as set forth, of amill-frame, a pair of rolls, j ournal-boxes for the rolls, those for oneof the rolls being movable to and from the other roll, a threaded lugsupported by the mill-frame, a screw provided with a handle and screwingthrough said lug and serving as a means for adjusting the appropriateone of said movable roll-boxes, a nut on said screw contiguous to saidlug, and an elastic toothed washer interposed between said lug and nut.

3. In a roller-mill, the combination, substantially as set forth, of amill-frame, a pair of rolls, a lever at each end of one of said rollscarrying at its upper end a journal-box and having its lower end pivotedto the millframe, a screw for adjusting said lever to and from theopposing roll of the pair of rolls, a lever at each end of the otherroll carrying a journal-box at its upper end and supported on a pivotintermediate of its length, and a spring acting between the lower end ofsaid lever and the intermediate portion of said first-mentioned lever.

4. In a roller-mill, the combinatiomsubstantially'as set forth, of amill-frame, two pairs of rolls, journal-box leversP for the support ofthe inner rolls, eccentric-shafts K, forming the pivots for said levers,hand-lever L for giving rotation to one of said eccentricshafts, cranksM and O, secured to said eccentric-shafts substantially at right anglesto each other, and link N connecting said cranks.

5. In a roller-mill, the combination, substantially as set forth, of amill-frame, a pair of rolls, pivoted journal-box levers for the supportof said rolls, means for adjusting the grinding distance between therolls, and a spring acting between the levers of the two rolls andserving to resist the inward movement of one roll and the outwardmovement of the other roll.

JONATHAN D. MAYVHOOD.

Witnesses:

A. O. Roenns, J. W. SEE.

